1. FIELD OF THE INVENTION
The invention relates to a buffered acrolein composition and method of enhancing the lifetime of acrolein in an aqueous medium by incorporation of a buffered organic acid, buffered inorganic acid or combinations thereof to the aqueous medium, and thereby adjusting the pH of the medium to from between about 2 and about 6.
2. DESCRIPTION OF THE PRIOR ART
Acrolein is used in numerous fresh water environments, as well as in brines and salt water, to kill aerobic, anaerobic, and sulfate-reducing bacteria, to remove aquatic weeds and snails, and to destroy algae, fungi, and other undesirable aquatic organisms. Of particular importance is the special use of acrolein in oilfield brines because of its potential biocidal action. This use of acrolein increases the efficiency of oilfield waterflooding and brine disposal operations. Acrolein also is used in oil field operations to scavenge deadly hydrogen sulfide. As the lifetime of acrolein is increased, the number of undesirable organisms destroyed increases, as does the amount of hydrogen sulfide scavenged.
Heretofore, it has been thought that the rate of the decline in acrolein concentration in an aqueous medium will inherently increase as the acid concentration increases and the pH decreases. This rate of decline in acrolein concentration has been reported to conform to the Hammett acidity function. Even the containers bearing commercial acrolein generally carry warning labels recommending that it be kept away from all acids, and particularly, strong acids, such as hydrochloric acid and sulfuric acid.
Acrolein inherently declines in concentration in aqueous media. The period of time between the initial acrolein injection and that time at which the acrolein becomes ineffective as either a biocide, herbicide, or hydrogen sulfide scavenger, is defined as the acrolein lifetime.
It has been found that variables such as temperature and composition of phases present in the aqueous based medium will cause both dilution and effective disappearance of acrolein. Since these aqueous environments generally flow, the acrolein will decline in concentration at considerable distance downstream from the injection point. Increasing the initial injection concentration of acrolein does not significantly alter the distance-time relationship at which the acrolein is depleted to an ineffective level.
One obvious solution involves the usage of multiple injection sites. However, this solution increases the cost of treatments involving acrolein in an arithmetic relationship to the number of injection sites. Additionally, since acrolein is a somewhat difficult material to handle, the multiple injection solution increases the danger of possible environmental accidents.